Calutron



Feb. 25, 1958 M. D.-KAMEN 2,824,967

CALU'IRON Filed 001. 31, 1944 s sheets-sheet 2 ATTORNEY.

Feb. 25, 1958 M. D. KAMEN 2,324,957

CALUTRON Filed Oct. 51, 1944 3 Sheets-Sheet 3 0 Q g s INVENTOR.

m s fl/HZT/N D. KAM N U ed States Pa en CALUTRON Martin D. Kamen, Berkeley, Calif., assignor to the United States of America as represented by the United States Atomic Energy Commission Application October 31, 1944, Serial No. 561,272

9 Claims. (Cl. 25041.9)

May 24, 1955, and is employed to separate the con- 7 stituent isotopes of an element and, more particularly, to increase the proportion of a selected isotope in an element containing a plurality of isotopes in order to produce the element enriched with the selected isotope.

For example, the machine is especially useful in producing uranium enriched with U Such a calutron essentially comprises means for vaporizing a quantity of material containing an element that is to be enriched with a selected one of its several isotopes; means for subjecting the vapor to ionization, whereby at least a portion of the vapor is ionized causing ions of the several isotopes of the element to be produced; electrical means for segregating the ions from the un-ionized vapor and for accelerating the segregated ions to relatively high velocities; electromagnetic means for deflecting the ions along curved paths, the radii of curvature of the paths of the ions being proportional to the square roots of the masses of the ions, whereby the ions are concentrated in accordance with their masses and means for de-ionizing and collecting the ions of the selected isotope thus concentrated, thereby to produce a deposit of the element enriched with the selected isotope.

More particularly, a calutron of the type noted ordinarily comprises an evacuated tank housing a removable ion source unit including structure providing a charge reservoir and a communicating charge ionizing chamber. In the operation of such a calutron, ordinarily the charge reservoir of the ion source unit contains a charge of a suitable uranium compound capable of being vaporized, such for example as uranium tetrachloride or uranium hexachloride; and after a given charge in the charge reservoir is vaporized, operation of the calutron is arrested and air is admitted into the tank. Then the ion source unit is removed from the tank and another charge is placed in the charge reservoir; and thereafter, the ion source unit is replaced in the tank and the tank is sealed and again evacuated. At this time, further operation of the calutron is resumed in order to vaporize the new charge contained in the charge reservoir.

While the operation of a calutron in the manner described is generally satisfactory, the operating conditions are not ideal in certain respects in that it is necessary to remove the ion source unit from the tank each time another charge is placed in the charge reservoir; and of course it is necessary. to admit air into the tank in order to increase the pressure therein each time the ion source unit is removed therefrom. Accordingly, the vacuum pumping apparatus associated with the tank must possess a larger gas handling capacity than is desirable.

Accordingly, t is an ob t 9 11;? r ssengtrgveq tgg to provide a calutron comprising an evacuated tank carrying an improved ion source unit having a charge reservoir that may be filled repeatedly with a suitable charge without appreciably increasing the pressure within the tank incident thereto.

Another object of the invention is to provide inla calutron comprising a tank having a removable wall, an improved ion source unit that is supported by the removable wall and includes structure defining a charge ionizing chamber disposed within the tank and a communicating charge reservoir disposed exteriorly of the tank, whereby the charge reservoir is readily accessible from theexterior of the tank.

Another object of the invention is to provide in a calutron comprising a tank supporting an ion source unit including structure defining a charge ionizing chamber disposed within the tank and a communicating charge reservoir, an improved arrangement controllable from the exterior ofrthe tank for regulating the flow of charge from. the charge reservoir to the charge ionizing chamber. H r A further object of the invention is to provide in an ion source unit comprising structure defining a charge ionizing chamber and a communicating charge reservoir, improved valve-mechanism for regulating the flow of charge from the charge reservoir to the charge ionizing ehamber.-

I A further object of the invention is to provide in an ion source unit comprising structure defining a charge ionizing chamber and a communicating reservoir housing a normally closed receptacle containing a charge, mechanism for opening the receptacle and then for regulating the" flow of charge therefrom into the reservoir and consequently into the charge ionizing chamber.

r A still further object of the invention is to provide in an ion source unit including a receptacle containing a charge capable of being vaporized, an improved arrangement for heating the receptacle, whereby the rate of vaporization of the charge contained therein may be controlled.

The invention both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which Figure 1 is a diagrammatic plan view of a calutron including an ion source unit embodying the present invention; Fig. 2 is a diagrammatic sectional view of the calutron taken along the line 22 in Fig. 1; Fig. 3 is a fragmentary longitudinal sectional view of the calutron ion source unit, taken along the line 3--3 in Fig. 4; Fig. 4 is a fragmentary plan view, partly in section, of the ion source unit; Fig. 5 is a fragmentary plan view of the inner end of the ion source unit, illustrating the position of the filamentary cathodes with respect to the asso- 'ciated arc-block; and Fig. 6 is a fragmentary fron-t elevational view of the inner end of the source unit, taken along the line 66 in Fig. 4, further illustrating the relative position of the filamentary cathodes and the arc-block.

Referring now more particularly to Figs. 1 and 2 of the drawings, there is illustrated a calutron 1i incorporating an ion source unit 11 embodying the features of the present invention. More particularly, the calutron 10 comprises magnetic field structure including upper and lower pole pieces 12 and13 provided with substantially fiat parallel spaced-apart pole faces, and a tank 14 disposed between the pole faces of the pole pieces 12 and 13. The pole pieces 12 and 13 carry windings, not shown, that are adapted to be energized in order to produce a substantially homogeneous and relatively strong magnetic field. therebetween, which magnetic field passes through the 114, and the various partshoused therein. The

tank 14 is of tubular configuration, being substantially r 52:82am? a 'crescent-shaped'in plan and comprising substantially flat tparallel' spaced-apart stop and bottom walls 15 and '16, 'upstanding'curved'inner and outerside walls 17. and 18;

and end walls 19"an1d 120. The end walls 19 and 20 close 7 the opposite ends of;the tubular tank 14 and are adapted to be removably secured'inplace, wherebyrthe tank 14 is hermetically sealed; *Also, vacu'umr'pumping apparatus 21.is associated with the tank 14,;Wherebyfth'einterior offthe tank '14 maybe evacuated to a pressure of the e ordertof l'i to 10*? mm. yHg.,rPr eferably,rthe component parts of the tank 14 are forrnedof steel,,the top and bottom walls and 16 thereof being spaced ashor-t dis tance' from the pole fac'esofjthe upper and lower-pole piece s 12 and 13 respectively, 'the'tankl14 being retained in such position in any suitable manner,.whereby the top and-bottom walls 15 and16 constitute in eifect polepieces slots 25 and 26 formed in the wall of the arc-block 23.

A suitable source of accelerating electrode supply is adapted to be connected between the arc-block 23 and the ion accelerating structure 36, the positive and negative terminals of the supply mentioned being respectively connected' to the arc-block 23 and to the ioniaccelerating structure 36. Furtherflthe positive terminal; of the accelerating electrodes supply is grounded;

The removable end wall "20 'suitably supports two collectorsblocksw and 40 arranged in:laterallysspacediapartrelation, each foimediofrstainless steel 'orthe. like, and being provided with two laterally spaced-apart-cavit-ies or 7 pockets which ,respectively communicate .with;two aligned slots formed in the w'all 'of' the collector block with respect to the interior of th e @1514, as explained more fully hereinafter. :7 V g The source unit 11 is carried by the removable end wal1 19 and the source unit 117 comprises aichar ge receptacle; 22 disposed exteriorly of the tank 1 4 andraicommunicatingarc-block 23 positioned within the tanlr 14.

An electric heater 24 is arranged in heat exchange relation Withthe'charge receptacle 22 and is adapted ttobeconnected to a suitable sour ceof heatersupply, whereby the chargereceptacle22 may be appropriatelyheated. The

arc-block 23 is of hollow construction and'the' cavity therein communicates with the interior of the chargef'receptacIe 22. Also, two laterally spaced-apart -upstandingrslots 25 and 26 are formed in the wall ofgthearcblocky23, disposed remoterfrom the charge receptacle 22. V

Further; theremovable end wall 19 carries two filamentar-y cathodes :27 and 28, adapted tobe connected to a suitable source of-filament supply, the filamentary cathodes 27an'd128 overhanging the upper end of the areblock'23-and arranged in alignment with-respect to the f the s ource of filament supply is connected by way of'a V series resistor 29 across a potential divider 30 of the resistance type, provided with an adjustable wiper 31. The two filamentary cathodes 27 and 23 are connected in 'series circuit relation .with respect to each other and to the potential'divider 30, the outer terminals of the filamentary cathodes '27 and 28 being respectivelyconnected to the outer terminals offth'e potential divider 30, and

" upper end of the'cavity formed therein respectivelyradjacent the upstanding slots 25 and'26. More particularly,

disposed remotefifromth removable end' wall 29. Specifically, the collector block 39 comprises'the two'laterally' spaced-apart pockets 41 andr42, respectively communicating'with the aligned slots 43 and 44 formed in the wall "thereofdi'sposed' remote frorn the removablejend wall 20; while the1collector block comprises the two lateral ly spaced-apart, pockets 45 and 46, respectively com-t. munic'ating, with fl1e alignedf slotsr-47 and '48"forme d in the wall thereof dispbsdlembt from the removabler end wall"20, 'Itis"noted thatthe'tWopocketsAl and 42'forrned'in the collector .block 39, as well as the two pockets 4'5 and 4w6 fo'rrned; fin,the collectorfblock '40, Y are adapted totreceive two gcdbstituentisotopes vof an, ele-.

ment that have beenseparate'd in the ,calutron 10, as explained more fully hereinafter; it

Further, the inner wall 17 :suitably supports [a tubular liner149, formed 10f copper for .the like, rectangular in vertical cross. section, disposedtwithin' the tank .14 and spaced from the. walls 15,416,917, andflS. .One' end of the tubularl-liner 49 terminates adjacent the ion taccelerating structure 36; and the'other. end ofthe tubular.

liner 49 terminates adjacent the collector blocks :39 and 40; the tubular liner .49 constituting an electrostatic shield for the high-velocity ions traversiug'curved paths between a the slit 3? formed in the ionaccelerating structure 3.5 and the slots '43 and 44 formed in the collector block 39, andzthe 'highevelocity" ions traversingcuryed paths bethe inner terminals of the filamentary cathodes 27 aud28 -11; being joined together and-connected to thefwip'er '31. Ac

V cordingly, it will be understood that' the potentialapplie'dj across the potential divider 30 via the'series resistor 29 from the source oftfilam'ent supply maybe appropriately divided across the'filamen'tary cathodes'27 and 28 by adjustment of the wiper'31 'of the potential divider'30. The arc-block 23, carries an" anode 32, disposed adjacent the lower end thereof and'arranged inalignment with t respect tottheo cavity formed therein. Also, the rare-block V 323 carries a eollimating electrode 33;disposed;adjacentf the upper end thereofiand having two elongated collimating slots 34'and 35 formed therethroug-h aud respectively arranged'imalignment with respect tothe fil'amentary cathodes rand 28,as ;well as in'common alignment; with "respect to the anode 32'a'nd the cavity formed inarc;

'block 23. Both the anode '32'and'the eollimating electrode 33 are electrically conneete'dtoithe' source unit;11,; which in turn is grounded; likewise, the ztankfel4 is' grounded Also', the filamentary cathodes 27 and ZSMandJVthe'. cooperating anode 32arej adapted: to hetjconnec terl to :a suitable source of arcsup'ply,

7 Further, the removable endiwallwl9 carries ion'acce'lerat -ing' structure 36; disposed; in spf bed-apa'rt; relation with r r'espectito-the wall ofjthe arc-block'23 in'which' the slots 25 -and 26 are formed. Morespecificallfitwo slits r37tands' V 38 *are-:f rurrnad v in the ion accelerating structure 13.6?and .7

arranged in substantial align rhnt with respecttofthe twotweenthe slit 38 formed in the ion acceleratingstrucx V ture 36 and the-slots .47 and 48 formedin the collector block-40,-as explainedumorerfully hereinafter Finally, lheim ular liner 4i9 is..electrically connected to the ion acceleratingr s'tructure 36' and to'the collector blocks 39 t and 40, theflcollector block-39 being electrically con;

nected'tothe-,eollectorblock-M}, Thus, -it will be under: stood that thesource unit 1j1 and the tank 14 are con-j nected' to the positive groundedterminal of the accelerat log-electrode supplygwhile theion accelerating structure 36; ,the tubul r liner 49, and. the collector blocks .39 and 40 areconnectedmto the negative ungrounded terminal ofthe"acceleratingelectrodeesupplyithe ion'accelerating W structure -36 ,the tubularliner and the collector blocks po'nent parts of the teale 14. '7 r elementtgto .bejtrelated is placed in; the i charge receptacle established therebetween traversing 'the' "tank "1142 The electric {circuit for t he jh eatjer is cl'ose'd whereby the 7 7 char e in e sha s ta e '2 ehee d er izedif The vapor fills' 'the' charg'e receptacle' -22 and is 39 and efl being electrically insulated ,from:;the com 7 assesses conducted into the communicating cavity formed in the arc-block 23. The electric circuits for the filamentary cathodes 27 and 28 are closed and the wiper 31 is adjusted with respect to the potential divider 30, whereby the filamentary cathodes 27 and 28 are heated and rendered electron emissive. Then the electric circuit between the filamentary cathodes 27 and 28 and the anode 32 is closed, whereby arc discharges are struck therebetween, electrons proceeding from the filamentary cathode 27 through the collimating slot 34 formed in the collimating electrode 33 to the anode 32, and from the filamentary cathode 28 through the collimating slot 35 formed in the collimating electrode 33 to the anode 32. The collimating slot 34 formed in the collimating electrode 33 defines the cross section of the associated stream of electrons proceeding from the filamentary cathode 27 into the arc-block 23, whereby the accompanying are discharge has a ribbon-like configuration; similarly, the collimating slot 35 formed in the collimating electrode 33 defines the cross section of the associated stream of electrons proceeding from the filamentary cathode 28 into the arc-block 23, whereby the accompanying arc discharge has a ribbon-like configuration. The are discharges in the arc-block 23 break up the molecular form of the compound of the vapor to a considerable extent, producing positive ions of the element that is to be enriched with the selected one of its isotopes.

The electric circuit between the arc-block 23 and the ion accelerating structure 36 is completed, the ion accelerating structure 36 being at a high negative potential with respect to the arc-block 23, whereby the positive ions in the arc-block 23 are attracted by the ion accelerating structure 36 and accelerated through the voltage impressed therebetween. More particularly, the positive ions proceed from the cavity formed in the arcblock 23 through the slots 25 and 26 formed in the wall thereof, and across the space between the ion accelerating structure 36 and the adjacent wall of the arc-block 23, and thence through the respective slits 37 and 38 formed in the ion accelerating structure 36 into the interior of the tubular liner 49. The high-velocity positive ions form two vertical upstanding ribbons or beams proceeding from the cavity formed in the arc-block 23 through the slots 25 and 26 and the respectively aligned slits 37 and 38, into the tubular liner 49.

As previously noted, the collector blocks 39 and 40, as well as the tubular liner 49, are electrically connected to the ion accelerating structure 36, whereby there is an electric-field-free path for the high-velocity positive ions disposed between the ion accelerating structure 36 and the collector blocks 39 and 40 within the tubular liner 49. The high-velocity positive ions entering the adjacent end of the liner 49 are deflected from their normal straight-line paths and from vertical planes respectively passing through the slot 25 and the associated aligned slit 37, and through the slot 26 and the associated aligned slit 38, due to the effect of the relatively strong magnetic field maintained through the space within the tank 14 and the liner 49 through which the positive ions travel, whereby the positive ions describe arcs the radii of which are proportional to the square roots of the masses of the ions and consequently of the isotopes of the element mentioned. Thus, ions of the relatively light isotope of the element proceeding through the slit 37 describe an interior arc of relatively short radius and are focused through the slot 43 into the pocket 41 formed in the collector block 39; whereas ions of the relatively heavy isotope of the element proceeding through this slit describe an exterior arc of relatively long radius and are focused through the slot 44 into the pocket 42 formed in the collector block mentioned. Similarly, ions of the relatively light isotope of the element proceeding through the slit 38 describe an interior arc of relatively short radius and are focused through the slot 47 into the pocket 45 formed in the collector block 40; whereas ions of the relatively therein.

vaporized in the manner explained above.

heavy isotope of the element proceeding through this slit describe an exterior arc of relatively long radius and are focused through the slot 48 into the pocket 46 formed in the collector block mentioned. Accordingly, the ions of the relatively light isotope of the element are collected in the pockets 41 and 45 of the'respective collector blocks 39 and'40 and are de-ionized to produce deposits of the relatively light isotope of the element therein; while the ions of the relatively heavy isotope of the element are collected in the pockets 42 and 46 of the respective collector blocks 39 and 40 and are tie-ionized to produce deposits of the relatively heavy isotope of the element Further, it will be observed that the beam of positive ions proceeding through the slit 37 formed in the ion accelerating structure 36 and directed to the collector block 39 intersects or crosses the beam of positive ions proceeding through the slit 38 formed in the ion accelerating structure 36 and directed to the collector block 40.

After all of the charge in the charge receptacle 22 has been vaporized, another charge may be placed therein without interrupting operation of the calutron 10, in a manner more fully explained hereinatfer, and subsequently After a suitable number of such charges have been vaporized in order to obtain appropriate deposits of the isotopes of the element in the pockets 41, 42, and 45, 46 of the collector blocks 39 and 40, respectively, the end wall 20 may be removed and the deposits of the collected isotopes in the pockets in the collector blocks 39 and 40 may be reclaimed in any suitable manner.

Of course it will be understood that the various dimensions of the parts of the calutron 10, the various electrical potentials applied between the various electrical parts thereof, as well as the strength of the magnetic field between the pole pieces 12 and 13, are suitably correlated with respect to each other depending upon the mass munbers of the several'isotopes of the element that is to be treated therein. In this connection, reference is again made to the previously-mentioned copending application of Ernest 0. Lawrence for a complete specification of a calutron especially designed for the production of uranium enriched with the isotope U and further reference is made to the copending application of Ernest 0. Lawrence, Serial No. 536,401, filed May 19, 1944, now U. S. Patent No. 2,714,664, disclosing a calutron of the multiple ion beam type of the general character described above. By way of illustration, it is noted that when the calutron 10 is employed in order to produce uranium enriched with U the compound of uranium which is suggested as a suitable charge in the charge receptacle 22 is uranium hexachloride; a calutron utilizing UCl is disclosed in the copending application of Francis A. Jenkins, Serial Number 563,952, filed November 17, 1944; and the compound of UCI as well as the process of making it, is disclosed in the copending application of Francis A. Jenkins, Serial No. 494,447, filed July 13, 1943, now U. S. Patent No. 2,572,156, granted October 23, 1951.

The compound UCl is very advantageous, as it may be readily vaporized and the molecular form of the vapor may be readily broken up to form positive ions of uranium with great facility. In this case, uranium enriched with U is collected in the pockets 41 and 45 of the collector blocks 39 and 40, respectively, and uranium comprising principally U is collected in the pockets 42 and 46 of the collector blocks mentioned. Also, it is noted that from a practical standpoint the deposits of uranium collected in the pockets 41 and 45 of the collector blocks 39 and 40, respectively, contain considerable amounts of U in view of the fact that this isotope comprises the dominant constituent of natural or .normal uranium. Furthermore, the deposits of uranium collected in the pockets 41 and 45 of the collector blocks 39 and '40 contain a considerably increased amount of U in view of iormed in the r'emovable en a 'charge receptacle 'fi bein'g-"carried bythe outer end of "lation therewfithmnd theirrstflatingpacking "54embedding v 7 I hereinafter; V

j imunigating withjt' extreme inner end 1111s :fact that :it sis 1m fordinarily feasible m separate-U and 'U -:in:the3 protlucti'on of relatively:large=quantities 7 ;of:u1'-aniumsenriclrecl with lU2 Ef0r eommerciali-purposes. Aecordinglypinthis rexamplertheuraniu'm deposited iri' th'e 7 pockets 4Land :01 ithe collectobhlocks 39 an'd:49

respectivelyfis:considerably enriched both :with 11 and 1 U2 5; :and considerably impoverished with respecttoll? V ascomparedita'.naturallor normal-uraninm. 1 a l y.-Refern'ng now qmore particularly tofEigs. 3 t'o' 6,= i'nclusive, aofi the drawings, Zther'e "are? illustrated: the str iic- :tural 'details soft theIsource eunit 1 1 -Which is 7 carried by theiremovable: end =-wa1l 19 9f the tank- 14 and --'cdmprises the tubular member and disposed exterioflyfifthe end-of the-'tnbular'membe A tank 14. r "The member '50 -1 lu'de afcylindrical inner tube 351-" antla cylindrica BHt'eQft Iibe'SZ; arranged in tele- V e'lica jele ric he ater "sis-ands suitfable' embeddin'g"packing-ofheatancFelectrial insulating referably; "the 'elecitrieheater 53' iclo's'ely "theelezric heater 'ssfdorn l tety-fifls the space-"between municating with this are chamber; "and the ftvvoestrips F61 "and'68-c6inprise'aflbortionofthe:Wall-stri1cture of-the-arc V chamber 62-and "a'rearr'anged imlat'erally spaced-apart relation to defin'e-" an tipst-anding =slot therebetiv'eenrcom :are. securedtto the member 56, respectively adjacent the strips 66, 67,"and GSandsPaced-a smrll distanceforward- 1y With'respect thereto. Morerparticularly, the' strips -69-and flfi'clefinean "'up'stantling' slottherehetween com v munica'ting with the arc'charnber 61; and the strips?!) and 71 define an "upstanding slot-therebetween come" mlinicatin'g With-the arc'eha'mberm. Thus, thei slot -d e "fined between the 'striips '6'6 and 67 and the s'lot define'rl 'b'e- 7 tween 'the -sti ips 69 and 70 constitute the com osite slot the tubes 51 and 52.". Tli'fisjfthe' tuhularmemberso may t "be heated in order, to ipre enrteen"den-simian of'ithe va or;

icontainedjin 'the iniierf tuliesl as ex lained mereffully V in any 'suitahle fn'anfie'r', the member 55 Being directly 7 secured and hermetically'sealed'to "the'inner'e'nd of the a 'in'ner tubeS'LTthe iinnerfen'il oftheitiibe 511 terminating in an Opening formed infthe 'rnemh'er '55. AIso, "the r'n'ember 5 5 is secured and he'rrnetic'ally sealed to-th'e outer tube 52' by an arrangement"including; airing T57 sur rouniiling the oiitertube 52; upstandin g'cavity-58 1 i'sformed inthernreniber iand communicates with" the inner tube 5l," the cavity 58' constituting a cl istributing chamber. 7 Also, 'two"hpstanding cavities 5 9 are formetl in the membefSSDn oppositeisikies Cfthefiistfihuting j'charnber "58 and receiverelectri'j: "heating elements 69. Thus,'the arc block '23 and'moreparticfila ril y the distribut- 'ingchamber therein may be heated in, orc lerrto pre-' vent condensation .o flthe contained vapor, "as explained more fully hereinafter.

ity. of laterally extending. longitndinally spaced-apart manifold passages 65, formed;inthememberSG and comistributifig" chamber 158. 7 Thus, the V he inner tub'e ,5lgcommunicates with the distributing'passage'58; whichin turn communicates with. the manifoldfpassages :whih are connected to V the openings 6 3 and, the-openings 63 and 4rr'espec tive'ly communicating with 'theQarc chambers 61 21111162. a 7 Three upstanding rst'n'psr66, 67;- 'and' 68, iforme'dlof tungsten orathezlike aresecxired fifth'e face-of-Zthe meni- 'ber,56 in,cooperating relation with the are chambers 61 .and 62. 1 More ;particularly; the t'woijs'trips "66 and 67 7' {comprise 5; p ortionl of the wal-l stfructnre of the are chamber 61 andfare arranged irirlaterally 'spaced apart slot defined between the -s'trips eziandfished-the slot defitietl between' thestfips Wanda constitilte theeomin 'the front Wall of the' arc-block 23 and 'commiinicating with the'cavity formec l thereimas previously noted, act ually communicate respectively with the arc'cha'mbe'rsfl and '62 formed in the memberse, Also; two upstanding or the likefar'e 'i'es'p'ectivly "arranged;in-the faiccham bars 61 and 62, -each'o'f the Balfie plates mentioned hav ing a series of, 'longitiifdinally spaced apart openings formed therein for '"apurpos'e more fully ic'plained -here-, V

Cathode structnre 72 is snppoite'dbver thewarc-hloek 23' and carries thetwo filamentaryfcatliodes r27 -a nd'28 previously noted; The cathodehstrhct iire'fli comprises '2. tubularl'shell'73 carried by the'rrrriovable end war-19 oftheta'rrkiupor: an insnlatoinrnot shown," and houses three conductors 74, 75,'and' 76', 'suitab ly insulated'froni reach ether and' respeetfiveiy terminating'tn three terminals 7 77, -78, and 79 which snppio'rtfthe filamentary cathodes 27 'aadiizs. ,Mere partieulan each-of'the two mam emar cathodes '27 511428 is substantially u' ha 'e'd and the leg thereof are removahly clamped in plaee upont'h teri i minals 77, 7s, and 79 by an arrangement menial detachable 'lgni iigi'plares $0,181, and 82'; 'Mo're sp cifi cally, the two 'l'eg'sfo fthe'filamentarycathodelTare respectively clamped upon the itwotiminals 77'alid 78: bythetWo clamping'pla tes fifi andSI;Qwhil'th two legs of the filamentary --cath'ode 28:.afe rifipectively clamped upon the two terminals is me -why the two clamping a plates 81fand f62.. -Accordingly the twpfenier legs fo'f the twofilamentary-cathodes 27 ahd-28Jare respect vely connected to the twdcohductor 74 and 76, and"the t'vvfo V inner legs-of :the twofilamentary cathodes 27 and '28 -are commonlyconnected to the con ductor '75 ihy thear rangement (jescribed.

The two fi-lamentary gcathdds '27 andZS overhang top Wall of-the-arc;bloekg23; as previously noted; andthe r c ollimat ing electrode;3 ;3 is 'cliregtlysecured to the mem-;

" ber 56,the sol-litigatingelectrode 33 having the two lat- {filamentary cathode Verally'jspaced-apartgancitransversely extending slots 34 p v med"there-in'angi respectively communicating;

with-the are chambers g and 62; More particularly, the V :isspaeedh short 'distan cef' above a V the eellir'nat'mgelect de-33 the centralgport-ion ofgtheg filamentary cathode; 27,;be-iag arranged -i-n -alignment with the eor respending transverse slot lal'formed inj-the' colliand eommunicating with the-"arc; a'mentary cathode'iii isspaced a K V withrth'earCchambei' Ma- V a a V The anodef32 v is" secured jtoztherli'ottom' Wall of me a V r elation"todefin'e angupstafidingf slot 'the'reh'etween-comarc bloek 23; zi'szprev'iously'nbtegl anddirectlytoihe lowei' V cathofie ZS being'i arranged p I e pending :transve'r'seslot :35; f 7 formed the 6ollhating -eleetrode 33and;communicating assess? end of the member 56, closing the lower ends of the arc chambers 61 and 62. The anode 32 is in alignment with the central portions of the filamentary cathodes 27 and 28 and the two transverse slots 34 and 35 formed in the collimating electrode 33. The negative terminal of the arc supply is connected to the conductors 74, 75, and 76, and consequently to the filamentary cathodes 27 and 28; and the positive terminal of the arc supply is connected to the arc-block 23 and consequently to the anode 32 and the collirnating electrode 33.

The ion accelerating structure 36 associated with the arc-block 23 comprises three upstanding laterally spacedapart strips 83, 84, and 85, supported by two laterally extending members 86 and 87, the ion accelerating structure 36 being disposed forwardly of the arc-block 23 and being supported upon an insulator, not shown, carried by the removable end wall 19 of the tank 14, as previously noted. The two strips 83 and 84 carry two electrodes 88, formed of tungsten or the like, and arranged in laterally spaced-apart relation to define the upstanding slit 37 in the ion accelerating structure 36, the slit 37 being arranged in alignment with the slot 25 formed in the front wall of the arc-block 23 and communicating with the arc chamber 61, as previously noted. The two strips 84 and 85 carry two electrodes 89, formed of tungsten or the like, and arranged in laterally spacedapart relation to define the upstanding slit 38 in the ion accelerating structure 36, the slit 38 being arranged in alignment with the slot 26 formed in the front wall of the arc-block 23 and communicating with the arc chamber 62, as previously noted. The positive and negative terminals of the accelerating electrode supply are respectively connected to the arc-block 23 and the ion accelerating structure 36, as previously noted.

The charge receptacle 22 comprises a charge bottle 90, formed of glass or the like and hermetically secured to an annular plate 91 which in turn is supported by an annular disk 92, directly secured to the outer surface of the removable end wall 19 of the tank 14. More particularly, the annular disk 92 surrounds the tubular member 50 and carries two supporting brackets 93 disposed on opposite sides of the outer end of the tubular member 50 and secured directly to the upper surface of the annular plate 91.

The lower end of an upstanding cylindrical shell 94 is secured to the central portion of the annular plate 91 and has an opening in the cylindrical side wall thereof into which the extreme outer end of the outer tube 52 of the tubular member 50 is secured. The upper end of the cylindrical shell 94 is secured to a ring 95, to which a removable annular cover plate 96 is secured. The portion of the outer tube 52 disposed between the shell 94 and the annular disk 92, as well as the portion of the shell 94 disposed between the annular plate 91 and the ring 95, is encased in a body of suitable thermal insulating material 97.

A centrally disposed opening 98, comprising a gas port, is formed in the annular plate 91; and the lower end of an upstanding cylindrical tube 99 is hermetically secured to the annular plate 91 about the port 98. The tube 99 is disposed within the shell 94 and has an opening in the cylindrical side wall thereof into which the extreme outer end of the inner tube 51 of the tubular member 50 is hermetically secured. The upper end of the upstanding tube 99 carries a substantially inverted cup-shaped member 100, also arranged within the shell 94. Further, the upper end of the upstanding tube 99 is hermetically sealed to a flexible bellows 101 arranged within the member An upstanding valve stem 102 is arranged for vertical movement within the upstanding tube 99 and is hermetically sealed to the flexible bellows 101, the lower end of the valve stem 102 projecting through the port 98 formed in the annular plate 91. mediate portion of the valve stem 102 is supported for More particularly, the interan annular bearing 166 carried in an annular opening formed in the cover plate 96. The bevel gear 105 is retained in position by a hollow block 107 secured to the cover plate 96, and is arranged in meshing engagement with a cooperating bevel gear 108, which is supported on a rotatable spindle 109 journaled in an opening formed in a block 110 secured to the cover plate 96, the outer end of the spindle 109 carrying a handle 111 to facilitate rotation thereof.

Accordingly, it will be understood that the spindle 109 may be rotated in either direction by the handle 111, in order to effect corresponding rotation of the bevel gear 108 carried thereby and consequent rotation of the bevel gear 105 in either direction. When the bevel gear 105 is rotated in one direction, the threaded end 104 of the valve stem 102 is forced to travel upwardly, whereby the valve stem 102 moves upwardly in the upstanding tube 99 with respect to the port 98 formed in the annular plate 91; and when the bevel gear 105 is rotated in the other direction, the threaded end 104 of the valve stem 102 is forced to travel downwardly, whereby the valve stem 102 moves downwardly in the upstanding tube 99 with respect to the port 98 formed in the annular plate 91.. It will be understood that the flexible bellows 101 accommodates movement of the valve stem 102 in either direction, retaining the hermetic seal established between the port 98 formed in the annular plate 91 and the upstanding tube 99 and the connected inner tube 51 of the tubular member 50. Further, it is pointed out that the outer tube 52 of the tubular member 50 is hermetically sealed to the removable end wall 19 of the tank 14, preferably by a welded joint, as indicated at 112. Thus, it will be understood that the substantially fluid-tight character of the tank 14 is not altered in any way by the fact that the interior of the shell 94 may not be hermetically sealed with respect to the exterior, in view of the fact that the removable end wall 19 of the tank 14 is hermetically sealed to the outer tube 52, which in turn is hermetically sealed to the ring 57; and the ring 57 is hermetically sealed to the member 55, which in turn is hermetically sealed to the inner tube 51.

The charge bottle 90 comprises a substantially spherical lower body portion 113 containing a charge 114 of UCl as previously noted, and a substantially cylindrical neck 115 providing an open throat into which the lower end of the valve stem 102 projects. More particularly, the neck 115 of the charge'bottle 90 terminates in an annular flange 116 that is hermetically secured to the lower surface of the annular plate 91 by an arrangement including an annular clamping collar 117 of the split type. The annular clamping collar 117 surrounds the neck 115 of the charge bottle 99 and engages the annular flange 116 thereof, the clamping collar 117 being secured directly to the lower surface of the annular plate 91 by an arrangement including a series of screws 118. Preferably, a flexible annular gasket 119 is disposed between the annular flange 116 carried by the neck 115 of the charge bottle 90 and the clamping collar 117, and an annular gasket 120 is arranged inan annular groove formed in the lower surface of the annular plate 91 in engagement with the annular flange 116, in order positively to insure a hermetic seal between the charge bottle 90 and the annular plate 91.

As previously noted, the body portion 113 of the charge bottle 99 contains a charge 114 of U01 which is originally sealed against the atmosphere by an arrange.-

V ;m'entincluding afrangible wall- 1=21-disposed in-th e=neck 7:1-15of the-charge"bottle"90,' the frangible 'wall-l2l being disposed belowthe =open '-throat of the charge b'o'ttle90.

V The lower end-of the'v'alve ste'm 102 projects t-hronghethe port ,98 formed in the annular plate '91 into the open throat of the charge bottle 90,-and carries avalve element 'or plate 122 which isadapted to cooperate 'with an annular V 1 ring 123 disposed in an annular. groove formed in the lower surface of the annular plate 91 in "surrounding V V 7 1 0, to the annular plate 91 by'settmg the screws 127.

relation withi respect tofltheport 98." Preferably, the annularring 123 is forrned of brassor the like'and con- 7 ;stitutes aseat for the valve port '98 formed in the annular 7 plate '91. -Also, the extreme lowerend of 'the valve stem 102 carries a fixture 124 disposedimmediately above the a 1 u :15 i5111'6d, opening the body portion 113 of the-charge-rece'pfrangible -wall 121, 'which fix'ture 124' is adapted to be moved-into' puncturing or striking engagement with the frangible wall 121.

In view of the above description, it will be understood 111 in order 'to'cause the valve stem 102 'to' be forced,

downwardly, causing the fixture 124'carried on the lower end-of the valve stem 102 to engage the frangible wall 121, whereby the wall 121; isybroken "or puncturedt ;725 V V i I teniperature within the range'80" to-180,C. as indicated Thereafter, "the'ha'ndle 111 'mayzbe operated; in order tocause the -valve stem "102to1be forced upwardly, whereby the valve element-122 is brought into cooperative relation "withrespect to the valve seat l-23 .iniorder to throttle th'e fiow ofvapor through the port 98'forn 1ed in the annular plate 91,'the charge 114j-con'tained in the body portion -113of'the charge bottle 90having been cbnvertedto vapor by heating, as explained more fully-hereinafter.

Further; the charge receptacle '22 coniprises a sub-' b'ottle'90. Under the conditions mentioned, the "charge stantially cup-shaped casing 125, carrying an annular ring a 126- adjacent the upper-edgeithereo f, the ring 126 being secured -to the annular plate 91 adjacenttheperiphery .thereof'by a plurality of screws 127. The outer surface r f the 'casing 1'25 supports a body of 'suitablethermal insulating material '128; and1 a substantially cup 'shap ed receptacle 129 is arranged within the casing 1251'nfs'urrounding and spaced-apart relationship with respect to' the charge bottle 90. A sealing'gasket130 *is'arfanged,

.rnutually betweenthe lower surface of the'annulai'i plate '91, the ring 126, and'the upper edge of the rec'eptacle -l'29,

7 thereby to; provide a' substantially fluid-ltight'sealthereibetween. The electric heater 24 is embedded inthe wall of the receptacle 129,j and a;body1132-ofa suitable light' oiLfraction, such as a parafiinic 'petr'oleumpil' fraction having-a relatively narrowpboiling range -is contained within the receptacle --129, submerging the body portion 113 'of the charge bottle 90, Further, ayth'ermocouple -is;carried -by-;th e annular plate '91 and-' extends into the body of oil 132; so that the temperature? thereof may be measure'dor recorded." fFinally, an upstanding helical -of;vapor therein; I

theareceptacle 129 carriedthereby, as;well as the charge 1 bottlei90; h:ave'beenfremoved from the plate 91, and u the handle lll' has been operated; in order to move the valve stern-102 upwardly, causing the 'valve element '122 to engage the sea't-123, ,the'port' 9 81f0rmed thef plate-9 1 is closed against the admission'ofair into 'the, upstandin'g tube 99and consequently intoi the'iank l, V whereby the: tank-14 is rendered substantially fluid-tight.

' A t this time, the clampingc ollar 117 is placed aboutitlie neck 115 of a charge bottlefit) which has=beenpreviously :plategrfilfz andrfiza prepared and sealed, the bodypor-tion 1'13 ofthe charge electric heater 134 is arranged within the shell '94 iii-sur a rounding relationship with re'spect to the upstanding tube} -99 and the member 100, in order to prevent condensation Considering now the 1 detailed operation "of the ion source .unit lliand assuming that the casing "125 a'nd *vapor-'toEbei-ionized, *due to the arrangement of the d 'respect to-the annular plate -91--andthe -screws-1i8yare set in order securely to clamp-the :a-nnular flange P1 1161 f disposed about the neck 115 -of-- thecharge -bottled!) against thelower-surface of theannularplate- 91;.and to-efieet a hermeticseal therebetween; At t histlme, the casing 125 supporting thereceptacle129 containingthe -body of-light oil-1-32 isbrought into position and secured carried on the extreme lower end thereof to striliethe ffrangible wall121, whereby this wallis broken er-puncmore" 9% and the contained chargeof U Cle 1 14 into cornmunicationwiththe interior of the upstanding tube-99 u ancl the cornmunicating inner tube 51. The circuitsior the electricheaters 24, 134, and, 53 are closed;- theeleg tricrheater 24 eifecting heating of the receptacIeIZQ. and

the contained b odyof oil 132, the 'el ectric'heater 13 1 -efiecting heating of the upstanding tube 99 and thernember7100, and the :electric heater 53 effecting heatingof theuinner tube51. l a 7 1 7 More particularly, the body of "oil 132 is heated to a ,by'fthe 'arr'ariger'iient including i the thermocouplel33,

w erebyme body portion 113 of thechargereceptacle f :90 isi'h'eatedfi'n order to effect heating ofthecharge of 1:30 UCl 1'14. ,At'th'is time, the interior of the t'ank 14 is evaenatedt ia pressure of the order of -t'o' lO- mrn. HgQWhereby a low pressure somewhat higher than that mentioned above ismainta'ined in the cavities in the arc- 7 block 23ta'nd conse'quently'in' the connecting inner-tube 51, the upstanding tube 99, and the interior of the charge 40 icornmunicating inner tube. 51. I a r V l The quantity of vapor supplied from'the charge bottle "9 0'through the port 98 formed in the annular plate '91 into the upstanding-tube 99 and communicating inner V V "tube 51 may be'regulated, both by controlling the ternperatureyof the body of oil 132 and consequently the 1arf'pIa'te 9 1. More particularly, at thistime the'han'dle re'cepta'cle 90 into {the upstandingtube99' through" the 55 port 98.-fc" rn:1ed-inthe annular plate'91 is throttled in'jan V iobviousinann'er.

u The Ucl vapor supplied froniitheecharge bottle into the inner tube 5l of the' tubnlarfmember '50 fl'owsi into the dis'tributing charnber 58 provided in 'theljmember zintoi'theinanifoldpassages=65fron1iwhieh itfflowslthrough "heating 'of the chargeof' 'UCl 114 and by theLvalve V ';.mechanisrn'including the valve element- 122an'd the valve 7 seat-l-23-associated with the port 98 formed'in the annu}. t

P111 may be manipulated inorder'to force thevalve stem 1'02 upwardly, the'reby bringing the valve element;

122 into cooperative relation with respect to the valve seat123, whereby the flow of vapor from the charge fss romi gya pan ofthearc-block 23; TheUclg'vapori fills the distributing chambef '58f andis distributed thereby the openings{GK-antl 'M EoHnedlin'the;niernber"56:into I V through the penings framed thoroughly and substantially uniformly filled lwith -the municating=bpenings63 and'fi g:and the associatedlbagflieg. j

a a a a l e e e l h bottlewponta mnga char e 114 otUCl anq the trangi- 5 --,filam y a ho e .7 and zs a're sated-and rendered;

. i3 electron emissive; and when the arc supply circuit is completed between the filamentary cathodes 27 and 28 and the arc-block 23, electrons are projected from the central portion of each of the filamentary cathodes toward the collimating electrode 33. More particularly, some or the electrons from the central portion of each of the filamentary cathodes 27 and 28 pass through the respectively associated transverse slots 34 and 35 formed in the collimating electrode 33, into the respectively associated arc chambers 61 and 62, and proceed toward the anode 32. Accordingly, the collimating electrode 33 causes a stream of electrons having a ribbon-like configuration to be projected through each of the arc chambers 61 and 62, whereby the vapor in each of the arc chambers mentioned is ionized.

When the accelerating electrode supply circuit is completed between the arc-block 23 and the ion accelerating structure 36, the positive ions produced in the arc chambers 61 are drawn through the upstanding slot 25 formed in the front wall of the arc-block 23 to form the beam of positive ions having the upstanding substantially ribbon-like configuration, proceeding through the slit 37 between the electrodes 88 carried by the ion accelerating structure 36; which beam of positive ions is projected through the evacuated tank space toward the cooperating collector block 39 in the manner previously explained. Also, when the accelerating electrode supply'circuit is completed between the arc-block 23 and the ion accelerating structure 36, the positive ions produced in the arc chamber 62 are drawn through the upstanding slot 26 formed in the front wall of the arc-block 23 to form the beam of positive ions having the upstanding substantially ribbon-like configuration proceeding through the slit 38 between the electrodes 89 carried by the ion accelerating structure 36; which beam of positive ions is projected through the evacuated tank space toward the cooperating collector block 40. in the manner previously explained.

Accordingly, it will be understood that the source unit 11 comprises two gas ionizing devices which are supplied from a single source of gas, and that this source unit 11 in conjunction with the associated ion accelerating structure 36 comprises two ion transmitters, arranged to trans mit two beams of ions through the evacuated tank space in the tank 14 of the calutron to the associated ion collecting apparatus in the form of the two collector blocks or receivers 39 and 4b, in the manner previously explained.

Operation of the calutron 10 proceeds in the manner explained above until substantially all of the charge of UCl 114 contained in the charge bottle 90 is evaporated, at which time it is necessary to replace the substantially empty charge bottle 90 with another. This may be accomplished in a ready manner by manipulating the handle 111 in order to force the valve stem 102 upwardly, whereby the valve element 122 is brought into engagement with the valve seat 123, closing the port 98 formed in the annular plate 91. The screws 127 are removed, permitting removal from the annular plate 91 of the casing 125 carrying the receptacle 129 containing the body of oil 132. The screws 118 are then removed from the annular plate 91, thereby permitting removal of the clamping collar 117 and the spent charge bottle 90.

At this time, another charge bottle 90 containing a fresh charge of UCl 114 may be replaced, as well as the casing 125 carrying the receptacle 129 containing the body of oil 132, in cooperating relation with respect to the annular plate 91, all in the manner previously explained. At this time, the handle 111 may be again manipulated in order to break the frangible wall 121 carried by the new charge bottle 96), in order to open the charge bottle mentioned into communication with the port 98 formed in the annular plate 91, and thereafter the handle 111 may be manipulated in order to throttle the flow of vapor through the port 98 formed in the an- '14 nuiar late 91 after the circuit for the electric heater 24 is again completed, all in the manner previously explained.

In view of the above description of the mode of operation of the source unit 11, it will be understood that charge bottles may be replaced in a ready manner without appreciably increasing the pressure within the tank of the calutron and without serious interference with continuous operation of the calutron. Also, it will be appreciated that the mechanism carried by the source unit for breaking a new charge bottle into communication with the arc-block is also utilized for the purpose of regulating the flow of vapor therebetween.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In a calutron including a substantially fluid-tight tank provided with evacuating means and a removable wall, an ion source unit comprising a tubular member carried by said wall, said tubular member extending through an opening formed in said wall and being hermetically sealed thereto, a gas ionizing device carried by the inner end of said tubular member and positioned Within said tank, structure carried by the outer end of said tubular member and defining a gas reservoir disposed exteriorly of said tank and containing a charge capable of being vaporized, means including a first heating element carried by and in thermal contact withsaid structure for vaporizing the charge contained in said gas reservoir, said tubular member communicating with said gas reservoir and said gas ionizing device, whereby the gas produced in said gas reservoir as a result of the vaporization of the charge contained therein may be conducted through said tubular member and supplied to said gas ionizing device, and means including a second heating element carried by and in thermal contact with said tubular member between said gas reservoir and said gas ionizing device for preventing the gas conducted therethrough from condensing therein.

2. An ion source unit capable of being evacuated comprising a member having a normally opened port therethrough, a normally closed receptacle containing a charge and secured to said member in surrounding relation with respect to said port, and mechanism carried by said member for opening said receptacle and then for closing at least partially said port, whereby the charge in said receptacle is placed into communication with said port so that it is conducted therethrough and then the opening of said port is controlled in order to regulate the flow of the charge therethrough.

3. An ion source unit capable of being evacuated comprising a member having a normally opened port therethrough, a normally closed receptacle containg a charge capable of being vaporized and secured to said member in surrounding relation with respect to said port, means including a heating element carried by said member and surrounding said receptacle for vaporizing the charge contained therein, and mechanism carried by said member for opening said receptacle and then for closing at least partially said port, whereby the charge in said receptacle is placed into communication with said port so that it is conducted therethrough and then the opening of said port is controlled in order to regulate the fiow of the charge therethrough.

4. An ion source unit capable of being evacuated comprising a member having a port therethrough and pro vided with a surrounding valve seat, a valve stem extending through said port and carrying a valve element adjacent one end thereof and in proximity to said valve seat, a receptacle provided with an open throat and secured to said member about said port, whereby the one f end of said valve ,stem,.and said valve element are disposed in the open throat of said receptacle, ,said recep tacle containing ,a charge capable soft being vaporized and being normally sealed by an; ,arrangement including a puncturable wall disposed adjacent the throat thereof and in proximity to the'one end of said'valve stern,

means for vaporizing the charge containedin said receptacle, and means for imparting movement to said valve stem withrespect to said member, whereby the one end of said valve stem may be moved into puncturing engagement with the puncturable wall of said receptacle and subsequently moved to bring said valve element into cooperating relation with respect to said valv e seat. V

5. An ionsource unit capable of being evacuated com- 7 prising a member'having a port therethrough, and .pro-

vidcd with a surrounding valve seat a valve stem extending through said port and carrying a valve, element adjacent one, end thereof and in proximity to said valve 7 7 seat, a receptacle provided with an open throat andfsecured to said member about said port, whereby the one end of said valve stem andsaid valveqelemen'tsare 'diS- posed in the open throat of said" receptacle,.said re-" ceptaclecontainiug a charge capable of being vaporized and being normally sealed by an arrangement including a'frangible wall disposed adjacent the throat thereoftand in proximity to the one end of said:valve--stem;means for vaporizing the charge contained"in said receptacle,

and m'ean's for imparting movement to said'v alvefmtem with respect to said member, "whereby the one-end-pf 'said valve stem may be -movedintobreaking engagement with the frangible -wall;of= said-receptacle -a'nd s ubsequently moved to bring said valve'element intocpefating relation with respect to said val-veseat.

6. An ion source unit capable of beingevacuated'comprising'a member having a port therethrough,"a-'-eharge receptacle containing a charge capable of being v'aporw ized and secured to said'member in surroundingrelation with respect to said porhanother receptacle car ried -by said member and'surrounding said chargerec'eptaolela'nd containing a quantity of liquid immersing said}--ch'ai=ge receptacle,lmeans for heating the liquid contained said other' receptacle, thereby to vaporize the charge co'ntained in said charge receptacle causing the vapor to flpw V throughsaid port, :and means, including a valve "element operatively associated .with saidjport Ifor controlling lhe flow of vaportherethrough. V s .1 s; i is "-3 I V 7 An ionsourceunitcapableofrbeingevacuated coin- V prising .azmemberuhavinga port therethrough sa l-re'cep tacle containing a charge capable .of-being:vaporized. and secured. to, saidmember in surrounding relation; with re SPQGLIO. saidsporhranother receptacle .carried bynsaid member andsurrounding said vcharge receptacle and corn tain'ing ma quantityofliquid immersing l said..charge re-' s ceptaele,.lmeans. including a heatingf'elementt embedded 1 in theiwalLofsaid other receptacle .for heating theliquid COHLZiJJCdJIhBIClD, thereby to vaporize'rthefl charge contained insaidcharge receptacle causing the vapor to -flow through said port, and means including a'valve element aoperativelyhassociated with said port for controlling. the 7 flow of vapor'therethrough; a s a 8. An .ion. source unit ,capablelrof gbeing evacuated comprisingramem'herr having a portstherethrough and pro- 7 vided with, a" surrounding valve seat, -hollow structure including arfiexible rbellowsqhermetically .sealed to said memberfandp. communicating with said port, a valve element car-ried .by:. said .fleirible. bellows in proximity; to

said valve' seat,:a rec eptacle containinga gaseouschjar ge t t andgherrne tically y fiflalfid fi) said-,membendn .communication:withaidport andameans for imparting motion I to .saidiile rible bellows, thereby ;to control the position of said "valve elementiwithi respectntor said: valve seat,

whereby ,the fiowof gaseouswcharge; from said receptacle lectively,eontr.olled.-

through-.saidmjort into: said rhollows structure may be sefi-saiditubularemember and positioned i h s t ta sealed chas carried: by;and1-in:-thermal;contactwidth said; receptacle for vaporizing 1 said ;-,charge,- valve; mechanism s,-interconr necting-qsaid charge? receptacle and :the outergend @of;said

tubular-remember;.ineludings.rneans ;,;for;zbreakingi;the .rseal of said charge receptacle and subsequently controlling a the flow of vapor,aandiseeond heater-means carriedby and in thermal,;contact-with;'saidltubular member :for

preventing said-vapor-fr'om condensingi-thereinli j References Qitedl in the .file .of this ;patent E'UNITEDf-STATLESIPATEN'FS removable structure-defining .a normally V receptacle without; said tank;v heater :mea'ns' 

